Fix ‘Unkown host’ Error on Mac

Have you ever had one of your websites become inaccessible on only one of your computers? The site loads up fine on every other machine you try it on but on this one machine, nada. If you try to ping the domain you’ll likely be presented with an ‘unknown host’ error.

If your computer is a Mac you will likely first think to try dscacheutil -flushcache . However, this will not work for you unless you are using an older version of OS X. Now what you’ll have to do is the following:

sudo killall -HUP mDNSResponder

In most cases this is what will work for you. I won’t bore you with a lengthy explanation of why. Just try it.